My niece is a carsick FFer. I don't think SIL is much into car seats or ERF, even though she is a DS member & generally a pretty diligent researcher. It wouldn't have made a difference, though. That kid booted after 10 min RF in a moving car from birth until she flipped at just over a year that played a part in their decision to turn her at that time. Now (nearly 5yrs old) she's much better, but does still occasionally get sick if the ride is especially long or the conditions bad.